The Strong Heart Study, a study of cardiovascular disease (CVD) among American Indians, involves 13 Indian communities in Arizona, Oklahoma and North and South Dakota. Phase I, which began on October 1, 1988 included a medical review to determine mortality and morbidity for CVD in individuals age 45 to 74 years old between 1984 to 1988. In the Dakota Center, a physical examination was performed on 1522 members of the Oglaha Sioux, Cheyenne River Sioux and Spirit Lake Tribes, to measure prevalence and cardiovascular and peripheral vascular disease, and known and suspected risk factors. Follow up exams (Phase II and Phase III) were conducted on surviving embers of this cohort from 1993-1995 and 1997-1999. In addition, nine families that included 258 relatives of study participants and 68 of the original cohort participants (326 total) were included in the pilot Family Study of genetic factors related to CVD and its risk factors. This application proposes an extension (Phase IV) of the Strong Heart Study in the Dakotas The aims of family members examined in Phase III, to re-examine those 326 family members and to examine an additional 900 family members in 30 more families. The examination of the 1226 family members will include cardiac and carotid ultrasound studies, EKGs, applination tonometry, blood chemistries and lipids and DNA. Expanding the family study will allow complete investigation of genetic determinants of CVD.